Moisture indicator



y 9, 1950 G. D. METZGER 2,506,806

MOISTURE INDICATOR Filed Feb. 1, 1947 IN VEN TOR.

- Gozye D. [Meizyer iatentecl May 9, 1950 UNITED OFFICE.

2,506,806 Morsruan INDICATOR "George Me'tzger,Cincinnati, Ohio ApplicationFebruary 1, 1947,;Serial No. 725,843

'13Claims. '1

This invention rel-ates to a dew point and moisture indicating device adapted to determine the operating condition of mechanical refrigeration apparatus. 4 One of the objects of theinvention is togreatly facilitate and expedite'thedeterminaticnof ineificiency and troublesome servicing problems occurring'in mechanical refrigeration apparatus, caused=by thepresence-of water or moisture in thetrefrigerant. p h I Another object is to provide-an inexpensive, compact, and positive means quicklyapplicable to mechanical refrigeration apparatus, {for determining the cause of faultyoperation andinefficiency, whereby the apparatus may be restored to proper operating condition without substantial loss of time, and'possible impairment oi the-quality of perishable goods depending upon refrigeration for its wholesomeness or salability.

A furtherobject is to reduce toa minimumthe cost of serving such equipment asis-referred-to above. I Y

The foregoing and other objects are attained by the means described herein and illustrated upon theaccompanying drawing, in which:

Fig. l-isa diagrammatical view showing-acc nventional mechanical refrigerationapparatus incorporating the device f --theinvention. M n

Fig. 2 is anelevationatview partly broken away and showing in crosssection on an enlarged scale, the dew. point and moisture indicating unit of the invention. 7 7 i 'Fig. 3 is an enlarged elevational view of acartridge constituting part of the invention. V

It is a well knownfact that r the maintenance of refrigeration equipmentis:a troublesome undertaking, for I the reason that faults or impairments of operation are often elusive, and will vary under different conditions and environments. At times, the inefiiciency or --fail ure of operation may be traced to purely mechanical-or "electrical f maladjustment, =or 1 normal wear of parts, whereas on other occasions T the troublesis basically chemical of. nature. 'In'therpastfitherefore; it was the-practice of the mechanic or serviceman to check and-adjust -all susrictedme- "chanicaland electrical parts of-tl1e;apparatus,--in the hope of restoring'it to operativecond'ition without having to cope with thechemical phase involving the refrigerant-which heretofore required the use of elaborate testingequipment not generally-understoodby the serviceman. As 5 the result ofsuch; practices, -"many refrigeration system were leftin-worsemechanicalcondition by the serviceman,.than it was prior'to'the servicing thereof.

By means of the device herein disclosed, the

ordinary mechanic ,or Serviceman isenabled to 'qui'ckly,easily, and accurately. check the refrigerant for chemical deficiencies-which'in manyca'ses are attributable to the presence of water ormoisture 'in the circulatory system. 'Water or moisture will sometimes occur inLthe system by-reason of condensation processes, or possibly by reason ofcareless charging of the system with refrigerant. Irrespective of the-manner of ntry,

however, water or moisture-in the system .may

cause various operating deficiencies as it freezes inthe expansion valve, or constricts the evaporator coil. .It will'often cause serious mechanical difficulties bycombining chemically with'the refrigerantto form a corrosive compound destructive of metal parts such as .valves,'f1ttings, coils and thelike. "From the "foregoing, it will be understood that refrigeration apparatus servicing .IshouIdby-aII means include tests for thepreserice of water, or.moisture in the refrigerant, if a last- Ting=and eiiicient repair is to be effected. To

make the proper servicing procedure feasible,

and performable onthe job,-is one of the primary objectives of thepresentinvention. I

Referring. to the accompanying drawing-Fig; 1

illustrates. conventionally a refrigerationapparatus consisting ofthe :compress0r5, condenserf fi,

-receiver I, evaporator '8, and the'necessary pipe or tubing for connecting those elements in.a closed system. The pipe .9 is the pressure line which carries-refrigerant in the hot vapor state tolthe condenser .5, which intur-n delivers. refrig- .erant to the receiver '1. Apipe 4 leadingfrom the receiver carries theliquid refrigerantto a stances from the systemqasthe refrigerant cirr-ide or-kindred compounds. Thedesiccantgis Ttightly sealed within the casing in anysuitable .inanner, as by meansofa cover ie-fir-mlyrhdd in place upon the upper, open end Of the casing.

In the example illustrated the. cover is held in fplace'byfapivot'yoke f6 anda cooperative clampiingfscrew H fwhichbears updnfthe top .oflthe cover.

As is usual in'refrigeration systems, the refrigerant under pressure passes through condenser 6 and receiver 7, from which latter it is forced through the dehydrator by way of pipe 4, and leaves through pipe l0. Pipe in leads the refrigerant to an expansion valve i9 which directs the refrigerant in vapor form into the coil or evaporator 8. The vapor upon leaving the coil or condenser, flows through the pipe 29, which is sometimes referred to as the suction line, and is carried thereby to the compressor 5. The cycle above referred to is repeated as the vapor is placed under pressure by the compressor, and discharged into pipe 9 as a superheated vapor. The characters 2!, 22, 23, I3 and 24 indicate simply a series of shut-fi valves or cocks generally incorporatcd in the system to prevent loss of refrigerant as any component parts of the refrigeration apparatus undergo repair or dismantling. Such valves or cocks may be interposed in the system at any desirable locations.

As the refrigeration apparatus operates, either continuously or intermittently, oil and water or moisture is trapped by the dehydrator l2 until such time as the desiccant within the dehydrator becomes overloaded, thereby making it necessary to renew the desiccant or drying substance. Heretoiore it has been impossible to determine the degree of saturation of desiccant within the dehydrator, so that through carelessness or indifierence on the part of the Serviceman, or through leakage of the pipes or fittings, water or moisture found its way through the entire system, resulting in inefficiency of operation and, in some instances, serious injury to the component parts of the apparatus. To overcome such an occurrence, the present invention proposes to connect into the circuit of the refrigerant at some suitable location, a dew point and moisture indicator which may be depended upon to visually indicate the presence or absence of Water or moisture in the system. While it is possible to connect the dew point and moisture indicator into the circuit at various other locations, there is indicated upon the drawing by way of example, a connection made with the casing of the dehydrator !2. Thus, the casing of the dehydrator is furnished with a fitting 25, preferably near the discharge end of the dehydrator, and through which may be exhausted a small quantity of refrigerant subsequent to its having passed through the desiccant of the dehydrator casing. The system may include a plurality of dehydrators such as 2, at which the tests may be made.

The fitting 25 is furnished with a small orifice valve 26, which may be in the form of a needle valve or other flow controlling element. The valve may have a suitable shut-off handle or actuator 2'! adapted for manipulation to permit the escape of refrigerant. The outer end 28 of the valve 26 may be threaded as illustrated upon Fig. 2, so that it may be coupled to a member 25 referred to as an indicator cartridge holder or connector, this element being in the form of a hollow body or tube serving as an expansion chamber and as a trap for lubricating oil released through valve 26. The tube has its opposite ends 36 and 3| fitted with plugs or couplings 32 and 33, respectively. Coupling 32 is bored and internally threaded at the location 34, to receive the threaded end 28 of the valve, and within the bore is located also a filter or pad 35 to absorb any lubricating oil passing from the system through the valve. Vapor passing the filter 35 enters the expansion chamber 36 through an axial bore 31 which is flared as at 41 for a purpose to be explained. As the vapor fills the expansion chamber, it drops therein any remaining oil or oil-water vapor, and continues through a small orifice 38 in the conical end 48 of the coupling or plug 33. This orifice 38 leads to an enlarged bore 39 of part 33, which is internally threaded to receive the externally threaded end ii! of the dew point and moisture indicating cartridge i. A filter or oil absorber pad 42 may be fitted within the bore 39, as shown.

It may here be observed that plugs or couplings 32 and 33 are fixed relative to the ends of holder 23 in any suitable manner. The fiare or concavity 4'! of plug 32 serves to aid in dispersing incoming gas throughout chamber 33, and in addition, it ensures complete drainage of any oil or moisture from the chamber when the holder is detached from valve 26 and stood on end subsequently to a testperiod. As to the other plug 33, it may be noted that the bore 38 in the conical end 58 is quite restricted in size, to avoid passage of any oil from chamber 36 to cartridge l The constricted bore 38, being formed at the apex of the cone, will be elevated above any reasonable amount of oil in the chamber, whether the holder is used in horizontal or upright position, so that flow of gas through bore 38 will not tend to carry over any oil into the indicator cartridge. Bore 3? preferably is not so constricted in size.

Initially, the dew point and moisture indicator cartridge 4| has its opposite threaded ends 40 and ll closed by means of removable caps 33 and 44 (Fig. 3), which serve to exclude atmospheric moisture from the cartridge normally. The body of the cartridge preferably is formed of glass or other transparent material, and its interior is packed with a chemical indicator shown at 55. This chemical indicator is of a type which will change color, or otherwise visibly alter its normal characteristics, when subjected to moisture in the refrigerant or gas undergoing test. The chemical indicator may be confined between two wads of porous or permeable inert material such as cotton or the like, indicated at 46-'6, and held in place by the bored retainers 52-52. As was previously pointed out, the opposite reduced ends of the cartridge 4! are threaded to enter either a cap such as 43, or an internally threaded plug or coupling such as 33.

To use the device of this invention initially, the serviceman will first apply the valve 26, being certain in advance that shut-off valves such as 22 and 2| are closed to avoid loss of refrigerant as the installation is effected. Thereafter, he may apply to valve 26 the holder assembly including the fixed plugs 32 and 33. Supplying himself with a number of indicator cartridges capped as illustrated by Fig. 3, the Serviceman thereafter may apply one of these to the coupling 33 in order to test the system for water or moisture content. In conducting the test, the cap 44 of Fig. 1 will be removed, and valve 28 opened for a short period of time not exceeding two or three minutes, which will be sufiicient to visibly alter the character or color of the chemical indicator within the cartridge ll, provided that moisture is present in the vapor released through valve 26. If no moisture is present, the indicator cartridge may be removed from coupling 33 and recapped, for use on another occasion. Should the chemical indicator reveal the presence of Water or moisture in the refrigerant undergoing test, the Serviceman will renew the desiccant or dehydrating material of the drying frigerant,

's-greases t ke sash cesarean acacia -est'dre the refrigeration opr ting'condition. It f'sliould "25 may be permitted to t val in co saengsutse unr tests. This valve, of course, will normally b'e'kept clo's'ed. g

While inthe "accompanying dr wingjth'e dew point and moisture indicator is shown applied to the Casing f deh ydlaltdi 12, {it "sh Ollld 'befappreciatd that it might "be applied at -'a y other location in the refrigeratin 'system wherejrerage-ram under pressure m y be present. For exam-pie, it may e"round-acmemenmn some instances to "apply the dew point and moisture indicator at the "suction service plug S9, or at the service plug 5d in thGl'IiEhiPl'QS 3T-1IB side of the compressor. The herein disclosed '-dew,pqim and moisture indicator will oper'atesatisfactorily in either the horizontal position illustrated upon Fig. 1 of the drawing, or me. vertical position made possible by interposing an elbow pipe fitting betweenfconnector 25 and valve 25 in Fig. 1 offthedrawing.

Various chemical indicators are available for c'hargingthe indicator cartridge 41, common examples of v which are calcium chloride, phosphorous pentoxi'de, and kindred chemical comcircuit including an expansion chamber body and a valve adapted to release a limited quantity of refrigerant from the circuit into'the expansion chamber for vaporizing the refrigerant, and a replaceable water and moisture indicator fremovably attached to said expansion chamber body, jsaid'indicator'being ihthe i'orm of atr'a'nsparent cartridge including a chemical visibly changeable as to at least one of its characteristics, when subjected to water-bearing refrigerant.

2. In combination, a refrigeration system dehydrator comprising a casing having a port for releasin to atmosphere a limited quantity of refrigerant, a moisture indicating cartridge, and a hollow cartridge holder interposed between the casing port and the cartridge, said holder including means for separating oil from the refrigerant in passing from the dehydrator casing to the moisture indicating cartridge.

3. In combination, a refrigeration system dehydrator comprising a casing having a port for releasing to atmosphere a limited quantity of refrigerant, a moisture indicating cartridge, and a hollow cartridge holder interposed between the casing port and the cartridge, said holder including means for separating oil from the refrigerant in passing from the dehydrator casing to the moisture indicating cartridge, the holder having opposite ends detachably connected to the casing and to the cartridge.

4. The combination which comprises, a dehydrator having a casing adapted for inclusion in the refrigerant circuit of a refrigeration system, said casing having a port for the release of refrigerant to be tested for the presence of place u n the dehydrator, for use controlling the release of re r ei a masters, var/s asses cs1 ture therein, a tridge hdlder com I hollow elongatedbodycon's'titu g an'exp chamber, said body 'fifi i ii D 51179 fi fi ta chably as beiatbd withgthe have nd withone end of the cartridge, and "'oilab'so' fm'ea ns in the holder "for precluding "passage f oil from the valve'niean's 'tothe indicating 'c'artri ge.

, 5 The combination which comprises, "afdehydratdr having'a casing adapted for iric'lii's'iohih the refrigerant ,ci'rcuitof a refrigeration systein, said lca'singjhavinga port for the releas ef'of ref frig'erant to be te's'tedforth'e presenceof'moisiture,

vaive jineans selectively operableffo'r fccntrbliing the release of refrigerant through said port, a hollow transparent'cartridg'e including means for visibly indieatillg the presence of moisture therein, a cartridge holder co nprising'ahollow elongated body constituting an expansion chamber, "said body "having opposite endsjdetachab'ly associatdvvith thevalve mea'nsand wimcneen'd, er the cartridge, andoilftrapping meansbetweenth'e dehydrator and 'the'indicating cartridge.

"6, An indicator for determining the "moisture "content of a refrigerant whichpompri'sesan'eldngate'd expansion chamber, said chamber having a restricted "opening at -"one end for introducing refrigerant into s'aidchamber, an indicator'ca'rftrid'ge fdeta'chably attached to the "other end "or said expansion chamber, said cartridge -l'iavir'ig transparent walls, and "a moisture "responsive chemical insaid cartridgefsaid clieinicalgiving'a visible hange when sub'j ed to moisture jb e'aring refrigerant, a restricted opening 'coinm'uniatih'g between the ex ansicn "chamber and the f id 7. An indicator for determining "the moisture content of'afrefrigerant Whichconiprises an "iongated expansionbhamber, said chamber ha'vi "g a restricted' o'pening atone 'e'ndfor introduciiigrefrigerant intofsaicl chamber, an indicator par,-

tncg detachably -aaaehed "to "the other end of said expansion "chamber, said "cartridge havin ve e michange when subjected to moisture bearing refrigerant, a restricted opening communicated between the expansion chamber and the cartridge, and a pad of oil absorbent material disposed between the expansion chamber and the cartridge.

8. In combination with refrigeration apparatus including a compressor, a condenser, an expansion valve, an evaporator and conduits forming an enclosed refrigeration circuit, an elongated expansion chamber, means for releasing a limited quantity of refrigerant from the circuit into an end of the expansion chamber, said chamber having a restricted port at the opposite end thereof, and a replaceable indicator cartridge removably attached to said chamber in communication with said port, said cartridge having a transparent wall and containing a chemical visibly changeable when subjected to water-bearing refrigerant,

9. In combination with refrigeration apparatus including a, compressor, a condenser, an expansion valve, an evaporator, and conduits forming a closed refrigeration circuit, an elongated expansion chamber, means for releasing a limited quantity of refrigerant from the circuit into an end of said expansion chamber, said expansion chamber having a restricted port at the opposite end thereof, a replaceable indicator cartridge removably attached to said chamber in communication with said port, said cartridge having a transparent wall and containing a chemical visibly changeable when subjected to water-bearing refrigerant, and an oil absorbent pad between said cartridge and said chamber.

10. An indicator for determining the moisture content of a refrigerant which comprises an expansion chamber, said chamber having a restricted opening at one end for introducing refrigerant into said chamber, an outlet fixture having a conical head at the opposite end of said expansion chamber, the apex of said conical head extending into said expansion chamber, a restricted discharge opening extending through the apex of said conical head, an indicator cartridge detachably attached to said discharge fitting in communication with said discharge opening, and a moisture responsive chemical in said cartridge, said chemical giving a visible change when subjected to moisture bearing refrigerant.

11. An indicator for determining the moisture content of a refrigerant which comprises an expansion chamber, said chamber having a restricted opening at one end for introducing refrigerant into said chamber, an outlet fixture having a conical head at the opposite end of said expansion chamber, the apex of said conical head extending into said expansion chamber, a restricted discharge opening extending through the apex of said conical head, an indicator cartridge detachably attached to said discharge fitting in communication with said discharge opening, a moisture responsive chemical in said cartridge, said chemical giving a visible change when subjected to moisture bearing refrigerant, and a pad of oil absorbent material disposed in the fitting between the discharge opening and the indicating cartridge.

12. An indicator for determining the moisture content of a refrigerant which comprises an expansion chamber, said chamber having a restricted opening at one end for introducing refrigerant into said chamber, the opening for introducing refrigerant into the expansion chamber being provided with a conical nozzle, said nozzle expanding into the chamber to cause refrigerant to swirl in the chamber and throw oil carried by refrigerant entering the chamber against walls of the chamber, an outlet fixture having a conical head at the opposite end of said expansion chamber, the apex of said conical head extending into said expansion chamber, a restricted discharge opening extending through the apex of said conical head, an indicator cartridge detachably attached to said discharge fitting in communication with said discharge opening, and a moisture responsive chemical in said cartridge, said chemical giving a visible change when subjected to moisture bearing refrigerant.

13. An indicator for determining the moisture content of a refrigerant which comprises an expansion chamber, said chamber having a restricted opening at one end for introducing refrigerant into said chamber, the opening for introducing refrigerant into the expansion chamber being provided with a conical nozzle, said nozzle expanding into the chamber to cause refrigerant to swirl in the chamber and throw oil carried by refrigerant entering the chamber against walls of the chamber, an outlet fixture having a conical head at the opposite end of said expansion chamber, the apex of said conical head extending into said expansion chamber, a restricted discharge opening extending through the apex of said conical head, an indicator cartridge detachably attached to said discharge fitting in communication with said discharge opening, a moisture responsive chemical in said cartridge, said chemical giving a visible change when subjected to moisture bearing refrigerant, and a pad of oil absorbent material disposed in the fitting between the discharge opening and the indicator cartridge.

GEORGE D. METZGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,103,985 Murray et al July 21, 1914 2,019,421 Link Oct. 29, 1935 2,429,694 King Oct. 28, 1947 

